OVERVIEW

Whenever an entire Galera cluster is not working then I should never stop or restart the entire cluster. I can refer to the below steps for it.                                                   

STEPS -

1 - Take ssh of MySQL/MariaDB node

Take the ssh / webssh of any one mysql/mariadb node in that cluster.

Go to /var/lib/mysql

open file grastate.dat

last line is safe_to_bootstrap: 0

change it to

safe_to_bootstrap: 1

Note: Bootstrap is the first node in a cluster. so we are saying it is safe for this node to be the first node in the galera cluster.

2 - Start mysql

Service mysql start

Once started, go to other 2 nodes and start mysql/mariadb one by one.

Note: Don't change grastate on the other 2 nodes.